Continuously rotating selectively operable apparatus for producing vibrato and tremolo



June 29, 1965 D. J. LESLIE 3,192,322 CONTINUOUSLY ROTATING SELECTIVELYOPERABLE APPARATUS FOR PRODUCING VIBRA'IO AND TREMOLO Filed Sept. 24,1962 INVENTOR. Dav/740 ti. 555415 United States Patent Office 3,132,322Patented June 29, I965 CONTINUOUSLY ROTATING SELECTIVELY OPER- ABLEAPPARATUS FOR PRODUCING VIBRATO AND TREMOLO Donald J. Leslie, ElectroMusic, '56 W. Del Mar Blvd.,

P.O. Box 2267!), Pasadena, Calif. Filed Sept. 24, 1962, Ser. No. 225,5837 Claims. (Cl. 179-1) This invention relates to speaker systems thatincorpor-ate rotary or oscillatory means for acoustically adding vibratoor tremolo to the sound. Particularly this invention relates to speakersystems for electronic organs.

During the course of play, an organist may desire to stop or start theacoustic apparatus. This may be done in two ways. One way is to startand stop the drive for the apparatus. The other way is to switch theorgan signal to fixed speakers without stopping the apparatus. Inertiaof moving parts prevents quick stoppingv and starting. Hence, the signalswitching method is best from the standpoint of instantaneous control.

When the organ signal is switched to stationary speakers, an undesirablefluttering sound results. This fluttering is due to the fact thatreflected sound waves strike the rotary or oscillatory device. Sincethis moving device has a non-uniform reflecting surface by its verynature, the undesired modulation results.

Doors or shutters might be used to shield the moving device when thesignal is switched to stationary speakers. But such doors or shutterswould require complicated, and probably noisy, operating structures.

Furthermore, such structures would have inertia making instantaneouscontrol again impossible.

The object of this invention is to provide rotary or oscillatoryapparatus for producing vibrato or tremolo that has substantiallyuniform sound reflecting characteristics whereby the objectionablefluttering efiect is eliminated.

In order to accomplish this result in the simplest possible manner, thesound reflecting characteristics of the apparatus are substantiallyreduced by applying sound absorbent material to the exterior of thedevice, and in some cases to the interior of the directional soundchannel.

This invention possesses many other advantages, and has other objectswhich may be made more clearly apparent from a consideration of severalembodiments of the invention. For this purpose, there are shown a fewforms in the drawings accompanying and forming part of the presentspecification, and which drawings, unless described as diagrammatic, orunless as otherwise indicated, are true scale. These forms will now bedescribed in detail, illustrating the general principles of theinvention; but it is to be understood that this detailed description isnot to be taken in a limiting sense, since the scope of the invention isbest defined by the appended claims.

Referring to the drawings:

FIG. 1 is a diagrammatic view of the system incorporating the presentinvention;

FIG. 2 is a top plan view of a rotary sound channel, a portion of thewalls being broken away and shown in section;

FIG. 3 is an axial sectional view taken along a plane corresponding toline 33 of FIG. 2;

FIG. 4 is a sectional view similar to FIG. 3, but illustrating amodified form of the present invention;

FIG. 5 is a sectional view taken along a plane corresponding to line 55of FIG. 4; and

FIG. 6 is a transverse sectional view similar to'FIGS.

2 and 5, but illustrating still another modified form of the presentinvention.

In FIG. 1 there is illustrated an electronic organ 10 that provides asignal output, as at a lead 11. This signal output may be appliedselectively to one of two speaker systems. One speaker system 12incorporates rotary apparatus that produces vibrato or tremoloacoustically. The other speaker system 13 does not produce vibrato ortremolo acoustically. A suitable switch structure 14 is provided forrouting the organ signal. In the present example, the switch structure14 is shown as a single pole, double throw switch. It will be understoodthat any suitable switch may be provided.

A lead or line 15 extends from one contact of the switch 14 to atransducer 16 that drives the rotary speaker system 12. A lead or line17 extends from the opposite terminal of the switch 14 to a transducer18 for driving the non-rotary speaker system 13. A movable arm 19 of theswitch 14 is connected to the organ output lead 11 and is selectivelyengageable with the contacts associated respectively with leads 15 and17. Accordingly, by manipulation of the switch 14, the organ signal isappropriately routed.

The rotary speaker system 12, in this instance, is of the type shown anddescribed in my Reissue Patent No. 23,323, dated Jan. 9, 1951.

A drum 20 provides a directional sound channel 21. The throat 22 of thechannel 21 opens at one end of the drum 20, and the mouth 23 of thechannel 21 opens at the side of the drum 20. The drum 20' is supportedfor rotation about its axis by bearing structures mounted upon walls(not shown) of a cabinet 24. The transducer 16 has a speaker cone thatis supported by the cabinet walls so as to register with the throat 22.Upon rotation of the drum 20 about its axis, the sound radiation patternis correspondingly rotated and tremolo and vibrato are imparted to thesound.

For rotating the drum 20, a motor 25 is provided that may be attached tothe cabinet 24. Pulleys 26 and 27 are respectively attached to the shaftof the motor 25 and to the drum 20. A belt 28 interconnects the pulleys26 and 27. The motor 25 is controlled by a switch 29 located at theorgan console 10.

In FIGS. 2 and 3, the drum 20 is shown in further detail. A peripheralwall 30 extends cylindrically, with end edges 31 and 32 spaced to formthe mouth 23 of the sound channel. Generally circular top and bottomwalls 33 and 34 overlie the top and bottom edges of the peripheral wall30. Openings are circularly arrayed at the center of the top wall 33 toform the throat opening 22 that is in registry with the speaker cone oftransducer 16. Walls 35 and 36 extend across the drum respectively fromthe opposite edges 31 and 32 of the peripheral wall 30 to form sidewalls of the channel 21. The throat opening 22 is located between theseside walls as shown in FIG. 2.

A curved wall 37 fits between the side walls 35 and 36. The curved wall37 has one end attached to the bottom wall 34 at the mouth 23 of thedrum. The curved wall 37 extends inwardly beneath the throat opening 22and upwardly where its other end is attached to the upper drum wall 33on that side of the throat opening remote from the mouth 23.

In order to provide uniform reflective characteristics of the drum 20,the sound absorbent material 38 is at tached to the exterior of the wall30. This sound absorb'ent material 38 extends from the edge 32 about theperipheral wall 30 to the opposite edge 31. The opening 23 of the drumitself has negligible reflective characteristics. The wall 30 also hasnegligible reflective characteristics due to the addition of thematerial 38. Accordingly, a more uniform reflective characteristic isprovided whereby fluttering is largely reduced.

The sound absorbent material 38 may be of any suitable material. Forexample, it may be balsa wood provided with parallel saw cuts to provideflexibility for wrapping about the drum and for increased soundabsorbent characteristics. Optionally, the material 38 may be of foamplastic material, such as urethane or the like.

In the form of the invention illustrated in FIGS. 4 and 5, a drum isprovided that is similar to the drum 20. In addition to sound absorbentmaterial about the peripheral wall of the drum, additional soundabsorbent material is provided at the mouth of the channel. Soundabsorbent material at 39 lines the side walls of the channel at themouth; sound absorbent material 40 lines the top Wall of the drum; andmaterial 41 lines the outer end of the curved wall.

The added sound absorbent material further decreases anynon-uniformities in the sound reflecting characteristics of the device,and the sound waves incident at any point upon the drum will bemodulated equally and independently of angular position of the drum.

In the form of the invention illustrated in FIG. 6, a rotary drum 20 isshown that has a number of peripheral openings 43 and 44. Speakerstructures 45 and 46 are attached to the inside of the drum and registerwith the sound channel openings as at 43 and 44. In this instance, thecones of the peakers form the major portions of the rotating soundchannels, the edges at the openings 4 3and 44 forming the outer terminiof such sound channels. Sound absorbent material 47 lines the exteriorof the drum 20". As in the forms previously described, the soundreflecting characteristics of the drum are substantially uniform.

The inventor claims:

1. In a system for acoustically adding vibrato or tremolo to sound:means forming a sound channel; a transducer for operating the soundchannel forming means; means for supporting the sound channel for cyclicmovement; motive means for causing the sound channel to move cyclicallyfor imparting tremolo or vibrato to the sound of said channel formingmeans; companion speaker means; switching means cooperable with thespeaker means and the transducer for determining the production of soundeither by said transducer 01' the companion speaker means; and soundabsorbent material supported exteriorly of the said channel formingmeans for cyclic movement therewith whereby fluttering is minimized uponoperation of the switching means to determine sound production by saidcompanion speaker means.

2. In a system for acoustically adding vibrato or tremolo to sound:means forming a sound channel; a transducer for operating the soundchannel forming means; means for supporting the sound channel for cyclicmovement; motive means for causing the sound channel to move cyclicallyfor imparting tremolo or vibrato to the sound of said channel formingmeans; companion speaker means; switching means cooperable with thespeaker means and the transducer for determining the production of soundeither by said transducer or the companion speaker means; and soundabsorbent material attached to said supporting means to providesubstantially uniform sound reflecting characteristics wherebyfluttering is minimized upon operation of the switching means todetermine sound production by said companion speaker means.

3. In a system for acoustically adding vibrato or tremolo to sound:means forming a sound channel; a transducer for operating the soundchannel forming means; means for supporting the sound channel for cyclicmovement; motive means for causing the sound channel to move cyclicallyfor imparting tremolo or vibrato to the sound of said channel formingmeans; companion speak- Cir er means; switching means cooperable withthe speaker means and the transducer for determining the production ofsound either by said transducer or the companion speaker means; andsound absorbent material attached to said supporting means and saidsound channel forming means to provide substantially uniform soundreflecting characteristics whereby fluttering is minimized uponoperation of the switching means to determine sound production by saidcompanion speaker means.

4. In a system for acoustically adding vibrato or tremolo to sound: arotary drum having one or more peripln eral openings; a speaker for eachof the openings and attached within the drum; means for rotating saiddrum at a rate to impart tremolo or vibrato to the sound; companionspeaker means; switching means for transmitting a musical signal eitherto each of seaid drum speakers or to said companion speaker means; andsound absorbent material about the periphery of said drum for making thesound reflecting characteristics thereof substantially uniform to avoidfluttering upon operation of said switching means to cause the musicalsignal to operate said companion speaker means.

5. In a system for acoustically adding vibrato or tremolo to sound: adrum having means forming a sound channel opening at the side of thedrum; means supporting the drum for rotation about an axis to impartorbital movement to the opening of the sound channel to impart tremoloor vibrato to the sound; and sound absorbent material wrapped about thedrum for making the sound reflecting characteristics of the drumsubstantially uniform.

6. In a system for acoustically adding vibrato or tremolo to sound: adrum having means forming a sound channel opening at the side of thedrum; means supporting the drum for rotation about an axis to impartorbital movement to the opening of the sound channel to impart tremoloor vibrato to the sound; and sound absorbent material wrapped about thedrum for making the sound reflecting characteristics of the drumsubstantially uniform; said sound absorbent material comprising semirigid material having parallel cuts for providing flexibility forwrapping about the drum as well as for increased sound absorbentcharacteristics.

7. In a system for acoustically adding vibrato or tremolo to sound: adrum having wall means forming a sound channel opening at the side ofthe drum; means for supporting the drum for rotation about an axis toimpart orbital movement to the said opening of said sound channel toimpart tremolo or vibrato to the sound; sound absorbent materialattached peripherally to the drum as well as along the said wall meansof said drum whereby the sound reflecting characteristics of the drumare substantially uniform with respect to angular position of the drumabout said axis.

References Cited by the Examiner UNITED STATES PATENTS 1,216,656 2/17Capps 18127 1,565,942 12/25 Jenkins l8133 X 1,914,099 6/33 Bedell 181271,992,268 2/35 Wente 18127 2,062,515 12/36 Hoschke 181-27 2,489,65311/49 Leslie l8127 2,618,352 11/52 Leslie l81-27 2,995,054 8/61 Leslie181--27 X 3,069,958 12/62 Arsem et al 181-27 X LEO SMILOW, PrimaryExaminer.

CHARLES W. ROBINSON, Examiner.

1. IN A SYSTEM FOR ACOUSTICALLY ADDING VIBRATO OR TREMOLO TO SOUND:MEANS FORMING A SOUND CHANNEL; A TRANSDUCER FOR OPERATING THE SOUNDCHANNEL FORMING MEANS, MEANS FOR SUPPORTING THE SOUND CHANNEL FOR CYCLICMOVEMENT; MOTIVE MEANS FOR CAUSING THE SOUND CHANNEL TO MOVE CYCLICALLYFOR IMPARTING TREMOLO OR VIBRATO TO THE SOUND OF SAID CHANNEL FORMINGMEANS; COMPANION SPEAKER MEANS; SWITCHING MEANS COOPERABLE WITH THESPEAKER MEANS AND THE TRANSDUCER FOR DETERMING THE PRODUCTION OF SOUNDEITHER BY SAID TRANSDUCER OR THE CAMPANION SPEAKER MEANS; AND SOUNDABSORBENT MATERIAL SUPPORTED EXTERIORLY OF THE SAID CHANNEL FORMINGMEANS FOR CYCLIC MOVEMENT THEREWITH WHEREBY FLUTTERING IS MINIMIZED UPONOPERATION OF THE SWITCHING MEANS TO DETERMINE SOUND PRODUCTION BY SAIDCOMPANION SPEAKER MEANS.